Backstab attacks should not work on creatures that can see through invisibility

argent77

Observed:
Even though the Cambion in the starting dungeon can see through invisibility my thief character was able to backstab him successfully (see screenshot below).

Expected:
Attack bonuses granted by a successful backstab attack should not apply to creatures that can see through invisibility.

How to reproduce:
1. Approach the creature with a decoy character so that the thief can get behind the target.
2. Select the thief and activate Hide in Shadows (or use any other means to turn invisible).
3. Place the thief behind the target creature and attack it.

Musigny

Whilst I agree with you, I just hope that Beamdog will keep the two notions separate.
Granting an automatic immunity to backstab may have side effects.

argent77

I agree. I have rephrased the line in my first post to more precise.

Dee

I'm shooting from the hip here, but isn't stealth different from invisibility? The ability to see things that are Invisible is different from the ability to see things that are hidden.

(It's been a while since I've looked at these specific mechanics, so I may be missing an idiosyncrasy of the engine.)

EDIT: What I mean to say is that the issue as described does not look like a bug to me. I'd check to see if the same behavior occurs when the thief uses a ring of invisibility instead of Stealth.

argent77

Both Invisibility and Improved Invisibility allowed me to successfully backstab the Cambion as well.

I haven't found anything specific in the AD&D Player's Handbook (Chapter 3) either. The relevant passage only states:

AD&D Player's Handbook said:

To use this ability, the thief must be behind his victim and the victim must be unaware that the thief intends to attack him. If an enemy sees the thief, hears him approach from a blind side, or is warned by another, he is not caught unaware, and the backstab is handled like a normal attack.

In the end it can probably be interpreted either way. However, from the technical perspective a thief hidden in shadows is treated like an invisible creature by the engine.

Musigny

@Dee
I think that most creatures protected by opcode 193 should also be protected by opcode 292. Perhaps not all of them though.
A creature with opc193 can cast spell on and attack invisible pc/creatures and IMHO it does not really make sense to allow a thief to backstab it. E.g. Kangaxx
There is a vague analogy with the protection from poison requiring both opcode 25 and an opcode 101 to be effective.

Independently from my opcode discussion related to quick patches, I think it would be good to see a reassessment of the whole invisibility/stealth mechanism even if this is to receive your confirmation that everything is ok from Beamdog's standpoint.
With SoD soon to be released (?), I guess that you already froze the core engine code version, perhaps for the next version...

In all cases, wouldn't such a reassessment help you design your next game ?
The guys who split the stealth feature to create Hide in Shadows and Move Silently were likely to have something particular in mind.